Nanofibrous PANI/TiO2 Composite Synthesized with Sea Urchin-Shaped MnO2 Nanostructure for High-Performance Pseudocapacitors

Abstract

This study presents a novel approach for the fabrication of polyaniline (PANI) and its composite polyaniline/titanium dioxide (PANI/TiO2) with a unique porous nanofibrous morphology that exhibits excellent performance for supercapacitor applications. The synthesis method involves a facile chemical oxidative polymerization of aniline monomer using nanostructured MnO2 powder, synthesized via a hydrothermal method, as an oxidizing agent in the presence of TiO2 nanoparticles under acidic conditions. The morphology, composition, and structure of the fabricated powders are comprehensively characterized using scanning electron microscopy (SEM) combined with an energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectra (FTIR). Electrochemical performance measurements, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), demonstrate that the as-prepared PANI nanofibers exhibit a specific capacitance of 800.25 F/g at a scan rate of 5 mV/s, which is attributed to the nanofibrous morphology that provides rapid charge transfer and easy electrolyte ions diffusion. Furthermore, the incorporation of TiO2 nanoparticles into the PANI matrix enhances the electrical conductivity and electrochemical stability, resulting in a high specific capacitance of 1110 F/g at a scan rate of 5 mV/s, while maintaining the cyclic stability with a retention rate of 95.3% after 1000th cycles. These results suggest that the as-prepared powders hold great potential for high-performance supercapacitor applications.